Chemokine is known as a basic protein having endogeneous leukocyte chemotactic and activating abilities and strong heparin-binding ability. At present, it is considered that chemokine is related to not only the control of infiltration of specific leukocyte at the time of inflammations and immune responses but also the development and homing of lymphocyte under physiological conditions and migration of hemocyte precursor cells and somatic cells.
Differentiation, proliferation and cell death of hemocytes are controlled by various types of cytokine. In the living body, inflammations are found topically and differentiation, maturation and the like of lymphocytes are carried out at certain specified sites. That is, various necessary cells migrate into certain specified sites and accumulate therein to cause a series of inflammations and immune responses. Accordingly, migration of cells is also an indispensable phenomenon in addition to differentiation, proliferation and death of cells.
Migration of hemocytes in the living body starts firstly in the development stage by the shift of hematopoiesis started in the AGM region into permanent hematopoiesis in bone marrow via fetal liver. Furthermore, precursor cells of T cells and thymus dendritic cells migrate from the fetal liver into the bone marrow and then into the thymus gland and cytodifferentiate under thymus environment. The T cell which received clone selection migrates into secondary lymphoid tissues and takes part in an immune response in the periphery. The Langerhans' cell of the skin activated and differentiated by capturing an antigen migrates into the T cell region of a topical lymph node and activates naïive T cell therein as a dendritic cell. The memory T cell performs its homing again into the lymph node via lymphatic and blood vessels. Also, B cell, T cell in the intestinal epithelium, γδ T cell, NKT cell and dendritic cell migrate from bone marrow without passing through the thymus gland and differentiate to take part in an immune response.
Chemokine is deeply related to the migration of these various cells. For example, MIP3β, SLC and its receptor CCR7 play an important role in the migration and homing of naïve T cell, memory T cell and the mature dendritic cell which captured an antigen into a topical lymphoid tissue for the dendritic cells to encounter efficiently with the T cells. The T cell and dendritic cell necessary for controlling antigen-specific immune responses are hardly observed in the secondary lymph node of a PLT mouse having deficiency in the expression of SLC (J. Exp. Med., 189(3), 451 (1999)).
MDC, TARC and its receptor CCR4 play an important role in the migration of Th2 cell into topical sites in immune and inflammatory responses in which the Th2 cell is related. In a rat fluminant hepatitis model (P. acnes+LPS), an anti-TARC antibody suppressed increase of the amount of ALT in blood and increase of the expressing amounts of TNFα and FasL in the liver and also improved lethality of the rats (J. Clin. Invest., 102, 1933 (1998)). Also, an anti-MDC antibody decreased the number of eosinophils accumulated in the lung interstitium and suppressed airway hypersensitivity in a mouse OVA-induced airway hypersensitivity model (J. Immunology, 163, 403 (1999)).
MCP-1 and its receptor CCR2 are related to the infiltration of macrophage into inflammation sites. An anti-MCP-1 antibody showed an effect to suppress infiltration of monocyte and macrophage into glomerulus in a rat anti-Thy1.1 antibody glomerular nephritis model (Kidney Int., 51, 770 (1997)).
Thus, chemokine receptors are greatly related to the control of inflammation and immune responses through a mechanism in which they are expressed at certain specified periods in variously specific cells and the effector cells are accumulated in a region where chemokine is produced.
Acquired immunodeficiency syndrome (called AIDS) which is induced by human immunodeficiency virus (hereinafter referred to as “HIV”) is one of the diseases of which their therapeutic methods are most earnestly desired in recent years. Once infection with HIV is completed in a CD4-positive cell which is a principal target cell, HIV repeats its proliferation in the body of the patient and, sooner or later, completely destroys T cell which takes charge of the immunological function. During this process, the immunological function is gradually reduced to cause fever, diarrhea, lymph node enlargement and the like various immunodeficiency conditions which are apt to cause complications with pneumocystis carinii pneumonia and the like various opportunistic infections. Such conditions are the onset of AIDS, and it is well known that they induce and worsen Kaposi sarcoma and the like malignant tumors.
As the recent preventive and therapeutic methods for AIDS, attempts have been made to, e.g., (1) inhibit growth of HIV by the administration of a reverse transcriptase inhibitor or a protease inhibitor and (2) prevent or alleviate opportunistic infections by the administration of a drug having immunopotentiation activity.
Helper T cells which take charge of the central of immune system are mainly infected with HIV. It is known since 1985 that HIV uses the membrane protein CD4 expressing on the membrane of T cells in the infection (Cell, 52, 631 (1985)). The CD4 molecule is composed of 433 amino acid residues, and its expression can be found in macrophages, some B cells, vascular endothelial cells, Langerhans' cells in skin tissues, dendritic cells in lymphoid tissues, glia cells of the central nervous system and the like, in addition to the mature helper T cells. However, since it has been revealed that the infection with HIV is not completed by the CD4 molecule alone, a possibility has been suggested on the presence of factors other than the CD4 molecule, which are related to the infection of cells with HIV.
In 1996, a cell membrane protein called Fusin was identified as a factor other than the CD4 molecule, which is related to the HIV infection (Science, 272, 872 (1996)). It was confirmed that this Fusin molecule is a receptor (namely, CXCR4) of stromal derived factor-1 (hereinafter referred to as “SDF-1”). In addition, it was confirmed also in vitro that the SDF-1 specifically inhibits infection of T cell tropic (X4) HIV (Nature, 382, 829 (1996), Nature, 32, 833 (1996)). That is, it is considered that the HIV infection was inhibited by the binding of SDF-1 to CXCR4 preceding HIV, thereby depriving HIV of a foothold for infecting cells.
Also at that time, it was discovered that another chemokine receptor CCR5, which is a receptor of RANTES, MIP-1α and MIP-1β, is also used at the time of the infection with a macrophage tropic (R5) HIV (Science, 212, 1955 (1996)).
Accordingly, substances which can compete with CXCR4 and CCR5 for HIV, or which can bind to HIV virus thus causing the virus unable to bind to CXCR4 and CCR5, could become HIV infection inhibitors. Also, there is a case in which a low molecular compound initially discovered as an HIV infection inhibitor was actually a CXCR4 antagonist (Nature Medicine, 4, 72 (1998)).
Based on the above, it is considered that the chemokine/chemokine receptors are deeply related to the inflammation, immune disease or HIV infection. For example, it is considered that they are related to the inhibition of various inflammatory diseases, asthma, atopic dermatitis, nettle rash, allergic diseases (allergic bronchopulmonary aspergillosis, allergic eosinophilic gastroenteritis and the like), glomerular nephritis, nephropathy, hepatitis, arthritis, chronic rheumatoid arthritis, psoriasis, rhinitis, conjunctivitis and ischemia-reperfusion injury, in the treatment of multiple sclerosis, ulcerative colitis, acute respiratory distress syndrome, shock accompanied by bacterial infection, diabetes mellitus and autoimmune diseases, and in transplanted organ rejection reactions, immunosuppression, metastasis prevention and acquired immunodeficiency syndrome.
On the other hand, in specification of WO97/11940, it is described that compounds of the formula (Z)
(wherein the atoms AiZ and BiZ are independently selected from carbon, nitrogen, oxygen or sulfur, provided that at least one atom of AiZ is carbon, and at least one atom BiZ is carbon;    the rings of the spirobicycle formed by AiZ and BiZ, respectively, may optionally be partly unsaturated,    pZ and qZ are independently numbers from 2 to 6,    mZ is a number from 0 to pZ,    R10Z is the same or different and is a non-interfering substituent independently selected from hydrogen, alkyl, halosubstituted alkyl, alkenyl, alkynyl, cycloalkyl, ═O, ═S etc.,    nZ is a number from 0 to qZ,    R0Z is the same or different and is a non-interfering substituent independently selected from hydrogen, alkyl, halosubstituted alkyl, alkenyl, alkynyl, cycloalkyl, ═O, ═S etc.,    the linking group -(LZ)- is a bond or a divalent substituted or unsubstituted chain of from 1 to 10 atoms selected from the group consisting of carbon, nitrogen, sulfur, and oxygen,    QZ is a basic group containing one or more basic radicals, and    R3Z is an acidic group containing one or more acid radicals) are useful in inhibition platelet aggregation.
In specification of WO98/25605, it is described that compounds of the formula (Y)
(wherein mY or lY are each independently 0, 1, 2, 3, 4 or 5,    R1Y is hydrogen, C1–8 alkyl, C2–8 alkenyl, C2–8 alkynyl etc.,    WY is a bond, C1–3 alkyl or C1–3 alkyl substituted with oxo etc.,    QY is —NR2—, —O—, —S—, —S(O)— or —SO2—,    XY is a bond, C1–3 alkyl or C1–3 alkyl substituted with oxo etc.,    YY-ZY ring is phenyl, naphthyl or hetero aryl.With the proviso that the definition of each symbol is a excerpt partially.) are useful as modulators of the chemokine receptors.